First time at the gym in 10 years due to injury - advice?

it would be best to use the elastic bands for a week or two just to ensure everythings alright and so that you dont strain the muscle. lunges with no dumbbells/light dumbbells isnt a bad idea. ultimately it just comes down to right nutrition so that your body operates properly and keeping things slow. as a personal trainer i would place my clients on the eliptical machines with low resistance to promote general growth throughout the leg muscles as well. hope this helps. if the pain comes back, i recommend checking with your doctor if you can. if not, slow it down some more and at all cost dont just 'tough out' pain, especially if it gets progressively worse.